Old revisions Add to book Export to PDF Fold/unfold all Book Creator Add this page to your book Book Creator Remove this page from your book Manage book (0 page(s)) Help Diode A component that controls the current to flow in a single direction only. This component is used to prevent reverse current flow that momentarily occurs when the door lock operates. If reverse current flow occurs, it can cause problems such as damage to the internal joint of the device relay, abnormal electromagnetic field generation, and shortening of the device's lifespan.